An electric power converter such as a DC-DC converter or an inverter, for example, is used for generating a driving power for energizing an AC motor, which is a power source for electric or hybrid vehicles.
The electric or hybrid vehicle or the like requires a large driving power in order to ensure a large driving torque from the AC motor.
For that reason, a heating value of semiconductor modules that incorporate a plurality of semiconductor elements therein constituting a power conversion circuit tends to become large.
Therefore, the electric power converter is provided with a cooler for cooling the plurality of semiconductor modules, and performs a thermal protection control that controls an operation of the semiconductor elements in accordance with a heating condition of each semiconductor module.
As such an electric power converter, there is one disclosed in Japanese Patent Application Laid-Open Publication No. 2005-143244, for example.
The Publication No. '244 discloses an electric power converter having a plurality of semiconductor modules, a plurality of cooling pipes for cooling the semiconductor modules, and a supporting member for supporting them.
The supporting member includes a pair of frames, a plate portion disposed on one end of the pair of frames, and a spring member disposed at another end of the pair of frames, and the semiconductor modules and the cooling pipes are supported between the plate portion and the spring member.
However, the electric power converter shown in the Publication No. '244 has the following problems.
In the electric power converter disclosed in the Publication No. '244, there is a possibility that a deformation during assembly or, a deformation due to a variation in shape may occur.
In the electric power converter, when pressing force is applied from the spring member to the semiconductor modules and the cooling pipes, reacting force is applied to the plate portion facing the spring member.
At this moment, since a rigidity of an open side of the supporting member opposite to the frames is lower than a side where the pair of frames are disposed, end portions of the open side in the plate portion facing the spring member may easily deform and incline so as to spread in an overlapping direction.
By the plate portion being inclined in this way, a pressure direction of the spring member is inclined toward the open side, and produces a bias in the pressure applied to the semiconductor modules and the cooling pipes.
For this reason, adhesion between the semiconductor modules and the cooling pipes are lowered in the open side.
Therefore, parts of the semiconductor modules in the open side will not be sufficiently cooled and the temperature of the semiconductor modules becomes high, so that there is a possibility that failure or performance degradation in the semiconductor module may occur.